In the following discussion certain articles and methods will be described for background and introductory purposes. Nothing contained herein is to be construed as an “admission” of prior art. Applicant expressly reserves the right to demonstrate, where appropriate, that the articles and methods referenced herein do not constitute prior art under the applicable statutory provisions.
A cell membrane constitutes the primary barrier for the transport of molecules and ions between the interior and the exterior of a cell. Electroporation, also known as electropermeabilization, substantially increases the membrane permeability in the presence of a pulsed electric field. The technique is more reproducible, universally applicable, and efficient than other physical methods and alternative biological and chemical techniques.
Conventional electroporation is typically conducted by exerting short electric pulses of defined intensity and duration to a cuvette equipped with embedded electrodes inside. Potter H., Anal. Biochem., 1988, 174, 361-373 The electrodes are commonly fabricated out of aluminum (Al), stainless-steel, platinum (Pt) or graphite, and arranged in a plate-to-plate manner. A pulse generator such as special capacitor discharge equipment is required to generate the high voltage pulses. By tuning the electric parameters, electroporation efficiency and cell viability (for delivery) can be optimized. Canatella P J et al., Biophys. J., 2001, 80, 755-764.
Although the traditional electroporation systems have been widely used, they require a high voltage input and suffer from adverse environmental conditions such as electric field distortion, local pH variation, metal ion dissolution and excess heat generation, resulting in low electroporation efficiency and/or cell viability.
In addition, the materials such as nucleic acids that are transformed into cells need to exhibit the appropriate activity following transformation. This often requires the assembly of the materials to be transformed into a form that allows, e.g., recovery, expression, transcription, translation, etc. of the RNA and/or proteins encoded by the nucleic acid. There is thus a need for automated methods of introducing assembled nucleic acids into cells in an automated fashion. The present invention addresses this need.